Such devices comprise a bearing of which one of the rings rotates and the other is fixed, the rotating ring being provided with a radial leading surface for coming into contact with the end of the fingers forming the diaphragm of the clutch. Between the rotating ring and the fixed ring are arranged rolling elements distributed evenly in the circumferential direction by means of a cage.
A non-rotating operating element supports the bearing and, by the action of a control member (mechanical, electrical or hydraulic), causes the thrust bearing to be displaced axially to make the leading surface of the rotating ring bear against the diaphragm of the clutch and to activate the clutch mechanism or system.
A self-centring element is generally interposed between the fixed ring of the bearing and the operating element, said self-centring element providing the axial connection between said two parts, whilst permitting, by its elasticity, a relative radial displacement therebetween. The bearing may thus be displaced in order to achieve a radial alignment of the rotational axes of the bearing and of the diaphragm, so as to be self-centred thereon.
In order to limit wear by friction between the fingers of the diaphragm and the leading surface of the rotating ring when releasing the clutch and engaging the clutch, it is possible to provide a wear ring made of synthetic material on said leading surface. For further details, reference could be made, for example, to the patent applications FR-A1-2 883 347, FR-A1-2 887 312 or US-A1-2006/0081439 illustrating such an element.
With such clutch release bearing devices, there are problems with the angular alignment of the axes of the bearing and of the diaphragm.
This impairs correct operation of these devices and reduces their service life, and may cause unpleasant sensations when releasing and engaging the clutch.
The present invention aims to remedy these drawbacks.
More particularly, the present invention aims to provide a clutch release bearing device in which the forces to be exerted on the clutch pedal are reduced when releasing the clutch and which is able to accommodate angular alignment errors of the axis of the bearing of the device and of that of the diaphragm of the control system of the associated clutch.
The aim of the present invention is also to provide a particularly economical device which is easy to manufacture and assemble.